Ready-to-drink, sugar-free beverages are much sought after by a large segment of consumers who are desirous of limiting their caloric intake. Aspartame is a high-intensity sweetener that has been widely accepted as a sugar substitute. Aspartame has been used for producing sugar-free, carbonated, ready-to-drink soft drinks for a number of years. It is well-known, however, that aspartame loses its sweetness over time in an acidic, aqueous environment. Carbonated soft drink manufacturers who enjoy a relatively quick distribution and use cycle time, usually involving direct store delivery of product from local bottling facilities, have therefore been able to use aspartame as the major or sole sweetener in their beverages. For beverage products where the distribution and use cycle may extend to a period of several months, the use of aspartame as the major or sole source of sweetness in acidic, ready-to-drink beverages has been a problem.
The loss of sweetness of aspartame in aqueous systems is known to be a function of time and pH, with loss of sweetness increasing with increased time and also increasing as pH moves away from 4.3, the optimum pH for aspartame stability. A manufacturer of aspartame has reported that the half-life of aspartame in an aqueous solution at pH 4 was 260 days; whereas, the half-life at pH 3 was only 116 days. Most non-dairy beverages, especially fruit-flavored beverages, have a pH of about 3.0 or below in order to impart a pleasant sour/tart taste to the beverage. Prior attempts to raise the pH of this beverage has resulted in a less desirable taste.
It is the object of this invention to formulate sugar-free, fruit-flavored aspartame-sweetened beverages where the pH is at least 3.2 and where the sour taste of the beverage is at least as preferred to similarly flavored beverages having a pH of 2.9. This invention will be useful in the formulation of new, sugar-free, fruit-flavored, ready-to-drink, aspartame-sweetened beverage products as well as in reformulating any such existing products.